const chokidar = require('chokidar')
const bodyParser = require('body-parser')
const chalk = require('chalk')
const path = require('path')
const Mock = require('mockjs')

const mockDir = path.join(process.cwd(), 'mock')

function registerRoutes(app) {
	let mockLastIndex
	const { mocks } = require('./index.js')
	const mocksForServer = mocks.map(route => {
		return responseFake(route.url, route.type, route.response)
	})
	for (const mock of mocksForServer) {
		app[mock.type](mock.url, mock.response)
		mockLastIndex = app._router.stack.length
	}
	const mockRoutesLength = Object.keys(mocksForServer).length
	return {
		mockRoutesLength: mockRoutesLength,
		mockStartIndex: mockLastIndex - mockRoutesLength
	}
}

function unregisterRoutes() {
	Object.keys(require.cache).forEach(i => {
		if (i.includes(mockDir)) {
			delete require.cache[require.resolve(i)]
		}
	})
}

// for mock server
const responseFake = (url, type, respond) => {
	return {
		url: new RegExp(`${process.env.VUE_APP_BASE_API}${url}`),
		type: type || 'get',
		response(req, res) {
			console.log('request invoke:' + req.path)
			res.json(Mock.mock(respond instanceof Function ? respond(req, res) : respond))
		}
	}
}

module.exports = app => {
	// parse app.body
	// https://expressjs.com/en/4x/api.html#req.body
	app.use(bodyParser.json())
	app.use(bodyParser.urlencoded({
		extended: true
	}))

	const mockRoutes = registerRoutes(app)
	var mockRoutesLength = mockRoutes.mockRoutesLength
	var mockStartIndex = mockRoutes.mockStartIndex

	// watch files, hot reload mock server
	chokidar.watch(mockDir, {
		ignored: /mock-server/,
		ignoreInitial: true
	}).on('all', (event, path) => {
		if (event === 'change' || event === 'add') {
			try {
				// remove mock routes stack
				app._router.stack.splice(mockStartIndex, mockRoutesLength)

				// clear routes cache
				unregisterRoutes()

				const mockRoutes = registerRoutes(app)
				mockRoutesLength = mockRoutes.mockRoutesLength
				mockStartIndex = mockRoutes.mockStartIndex

				console.log(chalk.magentaBright(`\n > Mock Server hot reload success! changed  ${path}`))
			} catch (error) {
				console.log(chalk.redBright(error))
			}
		}
	})
}
